Pipelines, and similar media handling and conveying systems, often accumulate air within them. The air can accumulate, for example, from bubbles within the media being conveyed (as used herein, media refers to a liquid that may contain solid or semi-solid material), by gasses that vent from the media, or during filling and emptying cycles of the pipeline.
It is often desirable to remove the accumulated air from the pipelines, and air release valves have been developed for this purpose. Traditional air release valves use the buoyancy of a float to close the valve. However, such designs suffer from a number of shortcomings, including the problem that each air release valve must be customized for different uses because of the varying pressures, flow rates, etc. that are observed along a pipeline. Further, existing air release valves often have limited pressure ranges, and cannot operate at the wide range of pressures that are sometimes experienced in pipelines. Specifically, higher pressure air release valves often require excessively large floats in order to provide sufficient buoyancy to overcome internal forces, such as extrusion forces along o-rings or against the orifice seal in the venting mechanism. In the alternative, mechanical linkages can be deployed to provide a mechanical advantage to overcome the forces, such as extrusion forces. Unfortunately, the use of a linkage in air release valves often results in increasing the number and types of wear and failure locations, resulting in a potentially less reliable valve that is also more expensive to maintain.
Therefore, a need exists for an improved air release valve, in particular an air release valve with broad operating pressures, including high operating pressures.